Abstract: An aircraft air-conditioning system provides ventilation, air-conditioning and fire protection for a below-deck stairwell and cargo hold that may be equipped with passenger sleeping compartment containers. An air mixing unit mixes fresh air and recycled air to supply mixed air through a first supply air main line (31) and a supply air unit (21) into the freight hold (4), and through a second supply air main line (32) into the stairwell (5). A trimming air unit (7A) provides hot bleed air from the aircraft engines into the mixed air supplied through the first and second supply air main lines (31, 32). An exhaust air line (11) extracts exhaust air from the freight hold (4), while an exhaust air supplemental line (15) extracts exhaust air from the stairwell (5), both of which are connected to an exhaust air main line with an exhaust air ventilator (16) that blows the exhaust air overboard. A bypass line (8) provides bypass air if needed for the demands of the ventilator (16).

Abstract: The below-deck space of an aircraft may be selectively configured as a freight hold or alternatively as a passenger sleeping cabin space by arranging a sleeping cabin container therein. An air conditioning system for this below-deck space provides air in a supply air main line (31), which branches off to at least one supply air delivery line (19). A first flange (23) is provided at the end of the supply air delivery line (19), and a seal collar (25) seals the end relative to the freight hold wall (29). When a sleeping cabin container is to be arranged in the below-deck space, a flap door (24) is pivoted into an open position, and the flange (28) at the end of a ventilation duct (27) of the sleeping cabin is connected directly to the flange (23).